1. Field of the Invention
The present invention relates generally to an apparatus for aligning and clamping a workpiece and in particular to an apparatus for aligning and pneumatically clamping frame assemblies.
2. Description of the Prior Art
In the assembly of various articles of manufacture, it is often desirable to temporarily clamp parts thereof in fixed relation to work surfaces or other parts. For example, when an article is being assembled the parts are often clamped together to apply pressure to glue joints therebetween. Also, the parts may be clamped together in fixed relation while being attached with various types of mechanical fasteners such as dowel rods, nails, screws, corrugated fasteners, staples and the like.
If all of the workpieces and parts are substantially identical, a machine like that shown in the Lancaster U.S. Pat. No. 2,182,154 can be provided and set up for the repetitious assembly of a number of identical parts or subassemblies, for example, frames. However, the Lancaster machine is not readily adaptable to the production of articles or subassemblies in various configurations, particularly where each article or subassembly is likely to have a unique configuration and dimensions.
For example, kitchen, bathroom and other cabinets for residential and commercial structures are often fabricated on a custom or one-of-a-kind basis so that they may be individually sized to properly fit the final dimensions of a particular space in the structure. A typical process for constructing custom cabinetry includes making frames for the cabinet fronts which generally include horizontal and vertical frame members secured together at right angle intersections to form openings for cabinet doors, drawers and the like. Back, bottom and side panels are then attached to the cabinet front frames to form enclosures. For aesthetics and to ensure that the cabinets and various parts thereof will fit properly, the cabinet front frames must be assembled with a relatively high degree of precision, and the right angle intersections should be as square as possible. Accordingly, the cabinet front frame pieces are generally laid out and squared with respect to each other before being fastened.
Typically, the cabinet front frame members are attached at their intersections by glue and mechanical fasteners such as nails, screws, dowels, corrugated fasteners and corner braces. However, it has been determined that most of the strength in such joints results from the glue, with the mechanical fasteners functioning primarily to reinforce the glue joint and to secure it until the glue dries. Thus, it is particularly important that the glue joints in a cabinet front frame be square and that the mating surfaces be clamped together, at least temporarily.
Heretofore, some cabinet fabricators and cabinet shops have employed pipe clamps for tightening the members against each other. However, pipe clamps often tend to cause the frame members to bow due to the pressure being applied slightly off center. Also, pipe clamps generally must be used in conjunction with other apparatus for squaring the cabinet front frames and tend to require time-consuming adjustments between each use on different size frames.
Other parts of a cabinet assembly which require alignment and clamping include the frames for raised panel cabinet doors wherein a frame is provided with a center panel which may embody, for example, an ornamental design.
Clamping and alignment devices are used in the construction of various other articles wherein clamping pressure is required and parts must be properly aligned. Without limitation on the generality of such articles, examples include frames of all sorts, furniture, containers, building components, etc.
Heretofore there has not been available an apparatus for aligning and clamping a workpiece with the advantages and features of the present invention.